-- Tags: replica DROP TABLE IF EXISTS parallel_replicas; DROP TABLE IF EXISTS parallel_replicas_backup; set allow_deprecated_syntax_for_merge_tree=1; CREATE TABLE parallel_replicas (d Date DEFAULT today(), x UInt32, u UInt64, s String) ENGINE = MergeTree(d, cityHash64(u, s), (x, d, cityHash64(u, s)), 8192); INSERT INTO parallel_replicas (x, u, s) VALUES (1, 2, 'A'),(3, 4, 'B'),(5, 6, 'C'),(7, 8, 'D'),(9,10,'E'); INSERT INTO parallel_replicas (x, u, s) VALUES (11, 12, 'F'),(13, 14, 'G'),(15, 16, 'H'),(17, 18, 'I'),(19,20,'J'); INSERT INTO parallel_replicas (x, u, s) VALUES (21, 22, 'K'),(23, 24, 'L'),(25, 26, 'M'),(27, 28, 'N'),(29,30,'O'); INSERT INTO parallel_replicas (x, u, s) VALUES (31, 32, 'P'),(33, 34, 'Q'),(35, 36, 'R'),(37, 38, 'S'),(39,40,'T'); INSERT INTO parallel_replicas (x, u, s) VALUES (41, 42, 'U'),(43, 44, 'V'),(45, 46, 'W'),(47, 48, 'X'),(49,50,'Y'); INSERT INTO parallel_replicas (x, u, s) VALUES (51, 52, 'Z'); /* * Check that: * - the table is not empty on each replica; * - combining the data of all replicas coincides with the contents of the parallel_replicas table. */ /* Two replicas */ SET enable_parallel_replicas=1, parallel_replicas_mode='sampling_key', max_parallel_replicas=3, parallel_replicas_for_non_replicated_merge_tree = 1; CREATE TABLE parallel_replicas_backup(d Date DEFAULT today(), x UInt32, u UInt64, s String) ENGINE = Memory; SET parallel_replicas_count = 2; SET parallel_replica_offset = 0; INSERT INTO parallel_replicas_backup(d, x, u, s) SELECT d, x, u, s FROM parallel_replicas; SELECT count() > 0 FROM parallel_replicas; SET parallel_replica_offset = 1; INSERT INTO parallel_replicas_backup(d, x, u, s) SELECT d, x, u, s FROM parallel_replicas; SELECT count() > 0 FROM parallel_replicas; SET parallel_replicas_count = 0; SELECT x, u, s FROM parallel_replicas_backup ORDER BY x, u, s ASC; DROP TABLE parallel_replicas_backup; CREATE TABLE parallel_replicas_backup(d Date DEFAULT today(), x UInt32, u UInt64, s String) ENGINE = Memory; /* Three replicas */ SET parallel_replicas_count = 3; SET parallel_replica_offset = 0; INSERT INTO parallel_replicas_backup(d, x, u, s) SELECT d, x, u, s FROM parallel_replicas; SELECT count() > 0 FROM parallel_replicas; SET parallel_replica_offset = 1; INSERT INTO parallel_replicas_backup(d, x, u, s) SELECT d, x, u, s FROM parallel_replicas; SELECT count() > 0 FROM parallel_replicas; SET parallel_replica_offset = 2; INSERT INTO parallel_replicas_backup(d, x, u, s) SELECT d, x, u, s FROM parallel_replicas; SELECT count() > 0 FROM parallel_replicas; SET parallel_replicas_count = 0; SELECT x, u, s FROM parallel_replicas_backup ORDER BY x, u, s ASC; DROP TABLE parallel_replicas; DROP TABLE parallel_replicas_backup;